Cerebral palsy (CP) is a non-progressive developmental disorder of the brain that results in reduced strength which negatively affects functional abilities and limits levels of activity. Lack of involvement in physical activity is one of the leading health concerns in the US and is associated obesity, cardiovascular disease, diabetes and other chronic diseases. The need for activity and exercise is especially acute for youth with physical disabilities, who participate in less physical activity than their non-CP peers and thus are at more risk for declines in health. The impact of having fewer options for activity is particularly detrimental for children with CP who tend to peak in ability prior to adolescence and then decline through their teenage years into adulthood. One major cause of decline is the disparity that occurs when muscle strength gains due to growth are not commensurate to gains in body size or weight. The disparity is often exacerbated by the interventions used to abate musculoskeletal and soft tissue changes that contribute to deformity, muscle tightness and joint contractures. Thus, children with CP have an overwhelming disadvantage for maintaining and improving strength, fitness and function. Stationary cycling is a proposed method of exercise for individuals that lack the balance, strength and coordination for upright exercise; however, we demonstrate that individuals with CP have impaired biomechanics that limit their cycling output. To enable greater cycling output, we employ functional electrical stimulation (FES) assistance and demonstrate the ability of FES assistance to produce higher heart rates, power output and cadences than children with CP are able to achieve on their own. Additionally, FES assistance enables cycling at a target powers for longer durations with less variance in cadence, however other than our initial investigations; we are unaware of any studies involving FES-assisted cycling in CP. The objective of this project is to improve physical conditioning and general lower extremity muscle strength for adolescents with CP using FES-assisted cycling. A prospective single blind, randomized controlled grouped experimental design will be conducted to investigate the relative effects of recumbent cycling training using volitional effort vs. training with volitional effort augmented by FES assistance compared to non-intervention controls on physical conditioning, muscle strength, and walking ability in adolescents with spastic CP and marginal walking ability. Both central and peripheral mechanisms for improvements in cycling performance will be investigated. PUBLIC HEALTH RELEVANCE: The purpose of the proposed work is to provide a means of vigorous exercise for individuals with CP that enables positive gains in cardiorespiratory function and muscle strength. With FES-assisted cycling, we hypothesize that FES will enable greater cycling output in individuals with CP by facilitating appropriately timed and higher muscle force activity during therapeutically dosed exercise. With improved ability we hope to facilitate interest in cycling for long term activity to maintain health and to maximize functional ability as the individual with CP ages.